August 2018 CDCB Sire Summary and New Lifetime Net Merit

Dr Marjorie Faust

Annually the American Dairy Science Association holds a convention at which many of the latest research papers on a wide variety of topics on dairy management and dairy foods are presented. This year’s convention was held June 24 – 27 in Knoxville, Tenn. Our columnist Dr. Marj Faust coordinated and chaired a session also supported by Interbull. Here she presents summaries of the papers on dairy genetics and genomic topics. Click here

After extensive research and testing, revised genetic models were put in place to improve and stabilize DPR and CCR for Holsteins and Jerseys. Improvements are expected to have the greatest impact for younger animals. As a result of the revisions, in the August evaluation data we expect to see DPR for younger Jerseys and Holsteins and CCR for younger Holsteins that are higher and more closely aligned with December 2017 results as opposed to their unusually low April 2018 results. The revised calculations and August 2018 fertility trait results also will confirm what most herd owners see and experience in their herds – females born today will generally be noticeably more fertile than those born 5 to 8 years ago,. The more accurate August 2018 genetic evaluation results illustrate that as an industry we’ve made significant genetic progress in improving female fertility.

In April 2018, the Council on Dairy Cattle Breeding (CDCB) released official genomic evaluations for six health traits for Holsteins. These six health traits evaluate genetics for resistance to Milk Fever (MFEV), Displaced Abomasum (DA), Ketosis (KO), Mastitis (MAST), Metritis (METR), and Retained Placenta (RETP). For the August 2018 evaluations, calculations for the CDCB lifetime profit indexes have been expanded to include these economically important health traits. As a result of these important additions, NM$, CM$, FM$, and GM$ now incorporate income and cost drivers accounting for genetic information from 36 traits using a lifetime profit function approach:

Larger revenue from cull cows sold for beef when Cow Livability (LIV) is higher meaning that fewer cows are prone to die, and when animals are larger/heavier (Body Weight Composite based on 5 Linear Type Traits).

The CDCB genetic-economic indexes (NM$, CM$, FM$, and GM$) are extremely thorough in accounting for revenues and costs (direct, indirect, and opportunity costs), as well as the genetic responsiveness of this diverse mix of traits. Today, this means that these indexes are powerful and comprehensive genetic decision making tools for dairies to select and breed more profitable generations of replacements.

Figure 1. illustrates the relative value of each trait or trait composite for each of the four CDCB lifetime profit indexes.

Dairy managers who desire to breed more profitable cattle that are robust and that can work across a range of systems in the U.S. as well as around the world can benefit from using one of the revised indexes – NM$, CM$, FM$, or GM$.

My input costs and sales prices for milk and cull cows differ from those used to compute the CDCB indexes. Will our herd see benefits from using NM$, CM$, FM$, or GM$?

This is an extremely important question and so will be considered in some detail.

Prices need to reflect market conditions in the future. It is important to clarify that input costs and prices used in selection indexes should not necessarily look like prices today. Instead, values used for genetic indexes need to reflect prices and conditions experienced by future generations of progeny, so 5 years from today and beyond. The researchers who built NM$, CM$, FM$, and GM$ have incorporated future-looking pricing information into the indexes.

Scientists also have asked this question about how useful indexes are when prices differ, because of the volatility in prices experienced across time by dairy operations.

Price differences are not a significant factor. When studying prices, researchers have found that indexes are quite robust to price differences. In practice, notable differences in the way two indexes rank the same group of animals occur primarily when the relationship between prices for different traits (milk:feed costs, as an example) are dramatically different. For U.S. dairies, market situations where such atypical price relationships exist tend to be the rare exceptions.

The key research finding is that indexes are moderately insensitive to most scenarios of price deviations.

For NM$ for example, this means that it will correctly rank sires and dams for different NM$-appropriate herds regardless of differences in their feed costs, labor costs, electricity costs, etc. differ.

Based on research results, a majority of herds can be confident in seeing benefits from using the most herd-relevant CDCB genetic-economic index – NM$, CM$, FM$, or GM$.

If normal price variability is not a significant factor influencing the real world performance of indexes, is there a factor that is more important?

Traits included. A significant factor in the resulting profitability delivered by using a given index is whether all of the economically important traits have been incorporated.

On the other hand, when an important trait is omitted, and especially omitting those with undesirable genetic correlations, profit gains resulting from using this index will be suboptimal.

With the incorporation of these 6 health traits, dairies can expect to see greater effectiveness of NM$, CM$, FM$, and GM$ in identifying sires and dams for creating progeny that are profitable in the future.

Which of the indexes is best for our production situation and milk market?

Net Merit $ will be a good tool for most dairies.

Dairies that receive little or no premium for protein in milk are expected to benefit from using Fluid Merit $.

Cheese Merit $ is a good choice for dairies in markets with large premiums for milk protein and true cheese yield formula pricing which places a negative value on the non-solids fluid portion of milk.

With a sizable emphasis on DPR, Grazing Merit $ will be most relevant to herds with limited breeding periods such those using seasonal grazing.

In a follow up column, we’ll look at these indexes (NM$, CM$, FM$, GM$) and other more proprietary ones that are available in our industry.

This article by Dr. Marj Faust is part of a series of regular columns on breeding and genetics she’ll be preparing for DairyBusiness Digital magazine.

She was an R&D executive at ABS Global and Genus plc, served on the faculty at Iowa State University, and provided consulting services in regulatory sciences to Novartis/Syngenta Seeds and FASS.

Based in Madison, Wis. area, she is a founder and principal of Agri Innova LLC and Data Driven Genetics, where she and her team partner with established and emerging organizations as well as farming businesses globally to build strategy and deliver innovation.

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